1. Field of the Invention
The present invention relates to a recording medium in which an object image obtained through a photographing optical system is electronically developed, and more particularly, to a device for controlling the electric voltage applied to the recording medium.
2. Description of the Related Art
Conventionally, as disclosed in Japanese Unexamined Patent Publication No. 5-2280 and U.S. Pat. No. 5,424,156, there is known a photographic material which is directly and electronically developed so that the developed visible image can be immediately obtained. In this specification, such a recording medium is referred to as an electro-developing recording medium, and an electronic still camera using the electro-developing recording medium is referred to as an electro-developing type camera.
Japanese Unexamined Patent Publication Nos. 5-165005, 6-130347 and 7-13132 disclose an electro-developing recording medium which comprises a liquid crystal display having a memory-type liquid crystal so that an image indicated on the liquid crystal display is kept even if the electric field applied to the liquid crystal display is removed. JP '347 and JP '132 disclose an electro-developing recording medium in which the electrostatic information recording medium and the electric charge storage medium are combined to form one body. Namely, in these electro-developing recording mediums, even if an electric voltage applied thereto is removed, the image formed on the electro-developing recording medium is kept.
On the other hand, in a camera using an ordinary silver halide film, it is known that a so-called panoramic size image can be obtained by covering upper and lower portions of the film aperture of the camera.
If a panoramic size image is desired in the electro-developing type camera, it is possible to cover the upper and lower portions of the film aperture with plates, for example. Such a construction, however, makes the mechanical structure of the camera complex, and makes the camera bulky.